« previous next »
Pages: 1 [2]  All   Go Down

Author Topic: Cb550 high idle  (Read 2987 times)

0 Members and 3 Guests are viewing this topic.

Offline Deltarider

  • Really Old Timer ...
  • *******
  • Posts: 8,187
  • ... but some animals are more equal than others.
Re: Cb550 high idle
« Reply #25 on: November 15, 2018, 12:19:01 PM »
Quote from: terrorshark on November 15, 2018, 11:44:32 AM
Needle is in center position.
Main jets are #85
Pilot jets #48
Enricher screw is backed out 2 turns.
Not sure what type of PD carbs they are.
Terrorshark, the position of the PD carbnumber is shown in the pics below. Also I added a scheme that lists the jetting of various carbs (specs.html). I must underline that I usually refrain from reposting data that I don't know the source of, in other words: I cannot stand for the integrity. I make an exception here, maybe it can help you.
« Last Edit: November 15, 2018, 12:43:41 PM by Deltarider »
Logged
CB500K2-ED Excel black
"There is enough for everyone's need but not enough for anybody's greed."

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,802
Re: Cb550 high idle
« Reply #26 on: November 15, 2018, 08:54:09 PM »
I suggest you raise the slide needle one notch.
Logged
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline BomberMann650

  • Holy Cow! I'm a
  • Really Old Timer ...
  • *******
  • Posts: 6,442
  • Dr. Bovinestein iBa#80333
Re: Cb550 high idle
« Reply #27 on: November 18, 2018, 07:33:48 PM »
Two Tired and StringBean both brought up the timing advancer.

I'd +1 that. 

Easy to confirm with a timing light.
Logged

Offline terrorshark

  • Full Member
  • *
  • Posts: 36
Re: Cb550 high idle
« Reply #28 on: November 28, 2018, 12:42:56 PM »
Advance is perfect. Hitting advance marks when running a timing light.
Checked for air leaks. None.

Still hanging up in idle. Above 3k will hang at around 3-3.5k. Above 5k. Will hang and slowly drop to 4K. Hang. Then drop to 2.5.

Plugs are reading rich. Fairly sooty.
Logged
'68 MV Agusta Tevere Motocarro
'72 Yamaha LS2
'74 MV Agusta 350b
'74 Honda CB550
'77 MV Agusta 350 Ipotesi
'00 MV Agusta F4

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,289
Re: Cb550 high idle
« Reply #29 on: November 28, 2018, 02:25:34 PM »
at what throttle position are they running rich?
if they are sooty just from general riding...it does not tell you WHAT fuel supply circuit needs adjustment.

Start with an idle plug chop with new plugs, and adjust IMS based on your results.
Logged
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline uksparky

  • Hot Shot
  • ***
  • Posts: 450
  • Track days
Re: Cb550 high idle
« Reply #30 on: November 28, 2018, 02:54:52 PM »
Messing around with the jets can cause this problem....if the carbs are PD46s then they should be 90 main ..pilot 42....here my guess..on the highway the main jet does its thing...coming down to idle pilot jet takes over.....i could be wrong guys but...coming down to idle the main jet is still feeding the fuel flow....not the pilot???...eg wrong jet size....or blockage pilot jets..how about past the pilot jets could be blockage there...
Logged
Present bike 1982 900C Custom
Pages: 1 [2]  All   Go Up
« previous next »